An early discovery: the alpha burst.

As it is when you got a new toy…. you want to play with it. Early in the 1990’s I saved money to buy biofeedback hardware and software, One of my first try-outs was with archers, since archery is a rather static sport and one has less potential for movement artifacts unlike e.g. a recording from American Football or MMA.

I connected the electrodes with the archers, in this case:

BVP or blood volume pulse, measuring the pulsation of the blood through the arteries (and a way to measure the heart rate)

Respiration by an elastic strap around the abdomen or thorax, measuring the frequency and the amplitude of the respiration (in this case the thorax)

EMG or electromyography, measuring if, when and how much a muscle works, often connected to a marker muscle which is important for the timing with the measured activity, in this case trapezius , whose activity change indicates the release of the arrow

Skin conductance which measures the sweat secretion, which is related to the activity of the sympathetic nervous system and emotion

EEG or electroencephalography, measuring electric brain activity in this case of the left and of the right brain. The EEG is measured over a certain frequency range, delta (1-4 Hz), theta (4-7 Hz) alpha (7-13 Hz), beta (13-30 Hz). Each of these specific bands can be analyzed separately by filtering.

EEG in archer

Archery is a good sport to measure also because the results are immediately and unambiguously available (you hit or you miss the target). In this case, bull’s eye was 10 points and each ring more distal, one point less, on a scale from 10 to 1.

Target

The measurements I did were real-time and could be reviewed afterwards as well.
Looking at the result I could not immediately see anything in particular related to a good or a bad shot.

3 shots

But making a change in the software I looked at the alpha band and something struck me. Every time, before a good shot, approximately 1.5 seconds before the archer releases the arrow, I saw a peak in alpha activity appear, especially at the left side of the brain. This also happened before a bad shot however, but at much smaller amplitude (the height of the peak). The result of the three shots shown above were 5, 8 and 10 points.
I asked myself, could there be a relationship between the quality of the shot and the height of the alpha peak or burst? To check this, I put a horizontal threshold line up at 15 microvolt that would give me a sound (a beep) when the amplitude would be over 15 microvolt and not when lower than 15 and I put up a headphone.

1 shot

I was sitting behind the archer, so he or she could not see me or hear the beep.

Set-up

Don’t forget I would hear that beep (= alpha-burst over 15 microvolt) around 1.5 seconds before the archer would release the arrow! So, basically if I was right I would know the result of the shot before it ever happened! The brain of the archer seemed to know it too, whereas the archer himself or herself would not, yet.
And I was right: the higher the alpha burst 1.5 seconds before the release of the arrow, the better the shot would be. The coach, who could not believe this could be true, wanted to make some bet with me and lost some money that afternoon.
This was the start of more work in this area. More questions would come up in my mind like: would this also apply to firearms shooting? I can tell you now: of course it does! The second question was: why does this happen, what is the mechanism behind it? And why the left side of the brain specifically? And the third question: what is the practical use of this phenomenon?
I’ll answer the first question only. I tested with Special Forces operators, with excellent shooters, average shooters (still much better than most of us) and with somebody who never had fired a gun before.

Operator shooting

It was obvious that the best shooter produced a much higher alpha amplitude before pulling the trigger, around 18 microvolts, the average shooter still 8 microvolts and the naïve shooter only 2-3 microvolts.
Shown below is the result of the experts shooter.

Excellent shooter

For me this is ultimate in sports psychology: psycho-physiology with tangible feedback and results and a glimpse into the “black box”.

 

About Henk Kraaijenhof

My name is Henk Kraaijenhof and I started this blog as a random collection of concepts, ideas, stories and events that are important or interesting to me in my work as an international performance consultant in a wide range of fields, and sometimes outside of my work. I will try to post a new entry every 3-4 days. Feel free to comment if you like.
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One Response to An early discovery: the alpha burst.

  1. Christiaan Oosterveen says:

    Love this subject! In the pas 18 months I am training my brain to operate on Alpha wavelength to improve my performance during exercise and business.

    I even used it by throwing darts.

    Meditation stimulates this skill by training the Prefrontale Cortex.
    Same with visualisation.

    The opposite happens with dart players who suffer dartritis.

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